Torque indicating power operated tool



Dec. 22, 1953 Filed April 12 1949 5o 29 3l (33a 4l flo H. O. GUMMERE ET AL TORQUE INDICATING POWER OPERATED TOOL I i Ei l INVENTOR.

Patented Dec. 22, 1953 TORQUE INDICATING POWER OPERATED Harold 0. Gummere and Eugene Linsker, Dayton, Ohio, assignors to Buckeye Tools Corporation, Dayton, Ohio, a corporation of Ohio Application April 12, 1949, Serial No. 86,982L 11 Claims. (Cl. 81-52.5)

This invention relates to a torque indicating power operated tool.

The invention is designed primarily for use in a motor operated wrench of the type in which the motor stalls when the resistance to the rotation of the nut exceeds the power of the motor. Usually the power of the motor of such a wrench is such that itwill stall. before the nut has been set to the desired tightness and the operator then actuates the wrenchA manually to further tighten the nut until he believes it to be set to the desired tightness. It is customary for an inspector to thereafter test the nuts which have been so set by applying thereto a torque wrench and to manually tighten such nuts as are not suiciently tight. 1

One object of the invention is to provide a power wrench having within itself means whereby the tightness of the nut may be ascertained and the proper tightness thereof assured before the wrench is removed from the nut, without the use of a separate device.

To this end a further object of the invention is to embody a torque testing device in a power wrench.

A further object; of the invention is to provide a power wrench with torque testing means including an indicator which will operate only when the nut has been set to the desired tightness.

a torque testing mechanism which can be embodied in a power wrench of a known construetion without material modification of the nut running mechanism of the latter.

A further object of the invention is to provide such a torque indicating power wrench which is of simple but strong construction and ecient in operation. Y Y

vOther objects of the invention may Iappear as the device is described in detail.

In the accompanying drawings Fig. 1 is a side elevation of a wrench embodying the invention; Fig. 2 is a longitudinal sectionaly view taken on the line 2-'2 of Fig..v 1 through the torque indicating mechanism and a portion of the h-andle; Fig. 3 sa section taken on the same line through the motor driven mechanism; Fig. 4 is a section taken on the line 4-4 of Fig. 2; and Fig. 5 is a section taken on the line 5--5 of Fig. 2. Y In these drawings we have illustrated one embodiment of the invention and have shown the same as embodied in a power wrench of a known type, but it is to be understood that the invention may take various forms and may be em- A further object of the invention is to provide n bodied in wrenches or other power operated tools of various kinds without departing from the spirit of the invention.

The power wrench per se, in Awhich the torque testing mechanism is embodied, is of a known construction and comprises a tubular supporting structure I0 in which is mounted a fluid operated motor II which is connected through planetary gearing I2 with a shaft I3. A worm I4 carried by the shaft I3 meshes with a worm gear I5 secured to a shaft I6, to the lower end of which is attached a Work engaging member I1, in the present instance a socket member to engage the nut which is to be set. The power wrench further includes a handle I8 which is normally connected with the supporting structure I0 by inserting the screw threaded forward end portion I9 of the handle in the screw threaded rear portion 20 of the supporting structure. The handle is provided with a fluid passage 2l communicating with the uid operated motor and adapted to be connected with a source of fluid under pressure, as by a exible hose 22. v f

In the present embodiment of the invention the torque testing mechanism has been interposed between the supporting structure I0 and the handle I8. This mechanism may take various forms and may be connected with the two parts of the power wrench in various ways but preferably it comprises an elongate member or rod 23 which is connected with the rear end of the supporting structure I0, extends rearwardly therefrom and is connected at its rear end with the handle I8. When, as in the vpresent instance, the invention is embodied in a uid operated wrench the rod 23 is preferably provided with a longitudinal passage through which fluid may flow from the passage in the handle to the motor, and the rod is here shown as a tubular element. The rod is of a relatively stii construction but is flexible by force applied to the rear end thereof. The rod may be connected with the supporting structure IU in any suitable manner and is here shown as tightly seated in a socket 24 forming a part of a connecting member 25 which is screwed into the threaded portion 20V of the supporting structure. Likewise the rear portion of that rod may be connected with the handle I8 in various ways. In the present instance it is mounted in a connecting member or head 26 having an opening 21 into which the rear end of the rod extends and having a rearwardly extending flange 28 to receive the threaded forward f portion I9 of the handle. The rod may be se- Acured to the head 276k in any suitable manner, as

aee'aeoo by forming in the head a transverse cut 29 and a longitudinal cut 3e to forni clamping members 3| which are drawn into clamping engagement with the rod by a screw 32, It will be noted that the threaded end I9 of the handle I8 is received in rearwardly extending ilange 28 in the same manner that the-forward endoffthexconneoting member 25 is received in rear portion 20 of supporting structure l0. This construction makes it possible for the removal of handle I8 from the supporting structure 2B andthe insertion of the indicator therebetween so that the device is applicable to existing tools, and thus tools may be used with and without the device oi the present invention.

The rod may be flexed by a force applied thereto by the handle I8, this handle being supported wholly by the rod and being movable transversely to the rod to flex the latter, and van indicator is associated with the rod and provided with a part arranged in the path of the fle'xing movement `of the rod and spaced from the rod when the latter is in its normal straight position. rIhe indicator may be of any suitable "character 'and the indication may be either visible or audible. Preferably the indicator comprises an indicating element `and an adjustable controlling device therefor., this controlling `device being supported 4in the path 'of the 'exible rod as above mentioned. The indicator is supported 'by the supporting structure i8 `and may be connectedtherewith in any suitable manner. In the present instance a casing 33 extends about 'the rod between the supporting structure and 'the-handle, and is here shown -as :hav-ing an axial opening or bore 34 through which the flexible element or vrod 23 `extends and which is 'of such a character that the rod may flex therein. vPreferably the casing 4is provided with an -elongatevslot 42 into which the 'free end portion of the rod may extend when the rod is flexed 'and which rconfines the movement of the rod to the desired plane. The casi-n'g 'may be rigidlyfattached to the supporting structure by providing the same at its 'forward end `with 'an axial recess to receive a boss 35 onthe connecting ymember 25 in which the socket 24 'is Iformed. In the 'arrangement shown it is secured to the boss by providing it with cla-mping members l"formed in the same manner as 'the clamping lingers 53| and drawn into clamping engagement with the boss by a screw 3l.

'Preferably the Avindicator is electrically operated and the indicating element is shown as a small `electric lamp 138, the ibase 39 of which is screwed into and has electrical contact with a socket 4@ mounted in the rear end portion 'of a second longitudinal bore y41 4vin the body of the casing. The'lamp may A'extend beyond the casing or the latter may have an opening through which the light passes, but Vpreferably the casing is provided 'with an end portion or cap 33a formed of translucent, :and `usually transparent, material,

said vcap having a recess to receive the lamp.

Thus the lamp is `protected against injury 'in 'the handlingiof the wrenc'howh'ile permitting the light vtherefrom Y'to be seen by the operator in various positions with relation vrto the wrench. The controlling device vfor the indicating elekment, which lin thepresent instance is a Y'circuit Aclosing device, is mounted on the "casing and is preferably adjustable lengthwise of the cas-- ing. lI'orthis'purpose the'casing'is-provided with a guide extending lengthwise thereof and 4on #which the controlling device 4is movablysupported. In the present arrangement the guide comprises a metallic plate 43 extending lengthwise of and across the slot l2v in the casing, insulated from the casing by a layer of insulating material, as shown at 44, and secured to the casing by insulated screws 45, as shown in Fig. 5. The guideplate 43 is provided with a longitudinal slot 4d in 'which the controlling device is adjustably mounted. As here shown the controlling device comprises a tubular member 41 extending through the slot and having a shoulder i8 spaced from the outer end thereof to engage the inner side lof the plate and having its outer end provided with an internal screw thread to receive a headed screw 49 by means of which the controlling device may be secured in adjusted positions lengthwise of the casing, a washer 5e being preferably interposed between the head of the .screw and the guide plate. A contact member 5I is supported by and extends inwardly from the inner end 'of the tubular member 41 and is here shown as a stud having a head `52 to engage a shoulder e3-within the tubular member and thus limit the inward movement of the stud. The stud is held normally in its extended position by a spring 5t and when in this position it is spaced an exact distance from the `unilexed rod in all adjustments thereof lengthwise of the rod, the guide plate 'being parallel Vwith the rod. The spring 54 permits 'the stud to yield .in the event the flexing movement oi the rod is continued after it has engaged the stud. vCurrent is supplied tothe indicator by a battery supported within the casing and here shown as comprising a plurality of dry cells 55 in ythe 'seicond bore il of the casing. The rear terminal 55 oi the battery' contacts a .second terminal 51 oi the lamp Se. The iront terminal of .the battery is connected by a spring 5S with a conducting member '5S mounted in the bore lil and connected by a conductor vSil Iand a screwV 6I with the conducting guide plate. Thus one side of the circuit is grounded on the casing land the rod .23 being electrically connected with the casing forms :a part of the circuit. When the rod is flexed rinto engagement 'with the contact member of .the indicator controlling device the current news from the ybattery through 'the conductor ell, the guide Vplate d3, controlling member 4l, rod '23, casing 33 and socket 4@ to the lamp and `from the lamp through the terminals 57 andf to the battery.

In the voperation o't the torque indicating .power wrench the handle ES is grasped in the hand of the operator, 'the 'work engaging memberfl is placed about the nut'which is to be set and fluid is admitted vtothe motor to 'operate-the latter fand .gto run the nut toward its seat. When fthe resistance to the rotation of the nut becomes greater than the power v`of the motor, the motor stalls. Upon the stallingei Ythe motor-the reaction thereoftends to move the wrench about the axisof the 'nut engaging'member in a ldirection opposite'the direction in which the latter is rotated by .the

motor, thisrlm'ovement being resisted 4by the ropervator who grasps 'theliand'le 18. rPrior'to the operation oi the wrench 'theindica'tor controlling device is adjusted alongv thefguide plate lto Yan `lindication corresponding to 'lthe valueof 'the torque required to set the 'nut with the required tightnut'v increases` un'til the rod lexes "sufcientlyto engagethe contact member and operate the indicator, that 'is illuminate the lamp 38, and the operator then knows that the nut has been set with the desired tightness. It will be obvious that the greater the torque required to completely set the nut the greater will be the flexing of the rod and that the distances which successive portions of the rod are moved by the flexing thereof decreases progressively from the rear portion of the rod toward the forward end thereof. Thus by positioning the contact member at a fixed distance from the rod and adjusting the same in a path parallel with the rod it can be adjusted to indicate a torque of any selected value within the range of the apparatus.

While we have shown and described one embodiment of our invention we wish it to be understood that we do not desire to be limited to the details thereof as various modications may occur to a person skilled in the art.

Having now fully described our invention what we claim as new and desire to secure by Letters Patent is:

1. In a power operated tool, a supporting structure, a rotatable work engaging member carried by said structure, power means connected to said structure at one end for rotating said work engaging member with relation to said structure and having an overhanging end opposite said connected end, manually operable handle means connected to said overhanging end for rotating said structure and said work engaging member about the axis of said member when the power of said power means is insuicient to rotate said member, and means carried by said handle means for indicating the Value of the rotative force asserted thereby on said work engaging member.

2. In a power operated tool, a supporting structure, a rotatable work engaging member carwhen-the' rotation ofsaid work engagingmember by said motor has been interrupted, ahandle for applying force tothe free .end of said rod vand said structure in a direction. to rotate said work engaging member in the direction in which it was rotated by said motor, said rod being flexible by force so applied thereto, an indicator adjacent said rod and operable by the flexing of said rod when the force applied thereto is of a predetermined Value, and means for connecting a fluid supply to said handle for delivery through said rod to said motor. Y

5. In a power operated tool, a supporting structure, a rotatable work engaging member carried by said structure, a fluid operated motor carried by said structure and drivingly connected with said Work engaging member, a tubular member secured at one end to said structure, extending rearwardly therefrom and communicating at its forward end with said motor, a handle secured to the rear portion of said tubular element, said tubular element being operableby said handle to move said structure and said work engaging member about the axis ofsaid member when the rotation of said member by said motor has been interrupted, said handle having a fluid passage communicating with said tubularA element and adapted to be connected, with a source of fluid under pressure, said tubular element being iiexible by force supplied thereto, and an indicator supported by said structure and controlled by the flexing of said tubular element.

6. In a power operated tool, a supporting structure, a rotatable work engaging member carried by said structure, a uid operated motor carried by saidy structure and drivingly connected with ried by said structure, power means connected to said structure and located adjacent said work engaging member for rotating said Work engaging member with relation to said structure, manually operable handle means connected to said power means on the side remote from said work engaging member for rotating said work engaging member and said structure about the axis of said movable member when the power of said power means is insu'icient to impart further rotation to said work engaging member, said manually operable handle means including a normally stationary element having supporting connection with said structure and having apart movable with relation to said structure by force applied to said work engaging member by said manually operable handle means, and an indicator operable by said movable p-art of said element when the force applied to said work engaging member is of a predetermined value.

3. A power operated tool as defined in claim 2 including means for adjusting said indicator for operation by the movement of said part of said element to a selected one of a plurality of positions.

4. In a power operated tool, a supporting structure, a rotatable work engaging member carried by said structure, a fluid motor carried by said structure and drivingly connected with said work engaging member to rotateA said member with relation to said structure, a rod forming a iiuid iiow conduit connected at one end with said structure and having at the other end thereof means for preventing the movement of said rod and said structure by the reaction of said motor said work engaging member, a tubular member secured at one end to said structure, extending rearwardly therefrom and communicating at its forward end with said motor, Va handle secured to the rear portion of said tubular element, said tubular element being operable by said handle to move said structuretand said work engaging member about the axis of said member when the rotation of said member by said motor has been interrupted, said handle having a uid passage communicatingvwith said tubular element and adapted to be connected with a source of iiuid underpressure, said tubular element being exible by force supplied thereto, and an electrically operated indicator supported by said structure and including a contact member spaced from said tubular element in the path of the iiexing movement of the latter.

7. InA a power operated tool, a supporting structure, a rotatable' work engaging member carried by said structure, a motor carried by said structure and drivingly Aconnected with said work engaging member, a rod secured 'at one end to said structure andextending rearwardly therefrom, a handle secured to the rear portion of said rod and operable to impart movement to said structureand saidwork engaging member about the axis of said member when the rotation of said member by said motor has been interrupted, said rod being flexible by force applied thereto by said handle, a casing extending about said rod between said structure and said handle and supported by said structure, an electrically operated indicator carried by said casing and including an indicating element and a circuit closing device adjustably supported on said casing and having a contact member spaced from said rod in the path of the exing movement thereof, a battery in said casing, and electric connections acca-,coe

7 between said indicating element, said contact member and said battery..y

8. In a power operated tool, a supporting structure, a rotatable work engaging member carried by said structure, a motor carried by saidstruc.- ture and drivingly connected with saidwor-k engaging member, a rod securedy at one end to said structure and extending rearwardly therefrom, a handle secured to the rear portion of said rod and operable to impart movement to said structure and said work engaging member about the axis of said member when the rotation of said member by saidV motor has been interrupted, said rod being flexible by force applied thereto by said handle plus a metallic casing supported by said structure and extending about said rod between said structureand said handle, a metallic guide carried by and insulatedfrom said casing, an indicating element supported by said casing and having one terminal grounded thereon, a contact member supported by said guide in spaced relation to and in the path of the flexing movement of said rod and electrically connected with said guide, ar battery in said casing having one terminal in contact with the second terminal of said indicating element, and a conductor connecting the other terminal of said battery with said guide.

9. In a power operated tool, av supporting structure, a rotatable work engaging member carried by said structure, a fluid operated motor carried by said structure and drivingly connected with said work engagingmember, a tubular element secured at one end to 'said structure, extending rearwardly therefrom and communicating at its forward end with said motor, Va handle secured to the rear portion of said tubular ele-V ment and operable to rotate said work engaging member when the rotation thereof by said motor has been interrupted, said handle having a iiuid passage communicating withv said tubular element and adapted to be connected with a source of iiuiolunder pressure, said tubular element being nexible by `force appliedrthereto', acasing supported by said structure between the same and said handle, said casing comprising an elongate metallic structure having a longitudinal bore-throughwhichsaid tubular element extends and in: which saidftubular element may have exing movement, said elongate structurefhaving a second longitudinal bore, a metallic guide member supported Aby and insulated from said elongatestructura an electric indicating element supported on saidr elongate structure with one terminal electrically connected therewith, a contact member supported by said guide member in spaced relation to and in the path of flexing movementrof said tubular element and electrically connected therewith, a contact member supported by said guide member in spaced relation to and in the path of exing kmovement ci said tubular element and electrically connected with said guide member, a battery in' said second'bore having one YterminaI v.thereof in contact with the ksecond terminal of saidy indicating element, and a conductor connecting the-second terminal of said batterywith said guide member.

l0, In a power operated tool, a supporting structure, a rotatable work engaging member carried by said structure, power means carried by said structure and permanently connected for driving said work engaging member, said structure having a socket at one end thereof, a handle `detachably securable to saidl socket for manualiy rotating said structure and said work engaging member about the axis oi' said member when the power required to rotate said work engaging member exceeds the power of said power means, and a torque indicating device insertable `between 4said handlev and said socket for transmitting the manual rotating force of said handle and providing an indication of the amount thereof.

ll. In a power operated tool, a supporting structure, a rotatable Work engaging member carried by said structure, iiuid power means carried by said structure and having ,a driving end for driving said work engaging member, said structure having a socket adjacent the end of p wer means opposite said driving end and having means for receiving a fluid vilow for operating said power means, a handle detaphably seeurabie to said socket for manually rotating said structure and said work engaging member about the axis of said member when the power required to rotate said 'work engaging member exceeds the pcwer of said power means, means on said handle for connection to a fluid supply, torque indicating means providing an indication of the amount of force appliedV manually to said work engaging member, a casing for receiving and supporting said torque indicating means, means in said casing for transmitting afiuid flow therethrough, and `means for detachabiy receiving and supportcasing in manual force transmitting and indicating relation between said handle and said socket and for transmitting said fluid flow'therethrough.

H. O. GUMMEREi EUGENE LINSKER.

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